Liquid jet recording head fabrication method

Abstract

There is disclosed a method for fabricating a liquid jet recording head having heat acting portions, communicating to orifices for liquid discharge, for applying heat energy to a liquid to form a bubble therein, electricity-heat converters for generating said heat energy, pairs of electrodes, and an upper protective layer, characterized in that the wet etching rate of electrode layer is higher on the upper portion in a direction of film thickness than on the lower portion.

What is claimed is: 
     
       1. A method for fabricating a liquid jet recording head having a base containing heat acting portions, liquid channels aligned over said heat acting portions and communicating to orifices for liquid discharge and a top plate covering said liquid channels, said method comprising the steps of (a) forming said base containing heat acting portions by a method comprising the steps of: (i) forming a heat generating resistive layer over a substrate: (ii) forming an electrode layer over said heat generating resistive layer; (iii) wet etching said electrode layer to form pairs of electrodes, wherein a wet etching rate is higher on an upper portion of said electrode layer in a direction of a film thickness of said electrode layer than on a lower portion of said electrode layer; and (iv) covering said pairs of electrodes with at least one protective covering layer;   (b) forming said liquid channels communicating to said orifices for liquid discharge over said heat acting portions on said base; and   (c) covering said liquid channels with a top plate.   
     
     
       2. The method for fabricating a liquid jet recording head according to claim 1, wherein said electrode layer is composed of a material containing impurities. 
     
     
       3. The method for fabricating a liquid jet recording head according to claim 2, wherein the content of impurities in said material containing impurities is greater on the lower portion than on the upper portion. 
     
     
       4. The method for fabricating a liquid jet recording head according to claim 1, wherein the material of said electrode layer is homogeneous, and the film formation condition of said electrode layer is selected so that the etching rate is higher on the upper portion of said electrode layer than on the lower portion thereof. 
     
     
       5. A method for fabricating a base containing heat acting portions for a liquid jet recording head, said method comprising the steps of: (i) forming a heat generating resistive layer over a substrate; (ii) forming an electrode layer over said heat generating resistive layer; (iii) wet etching said electrode layer to form pairs of electrodes, wherein a wet etching rate is higher on an upper portion of said electrode layer in a direction of a film thickness of said electrode layer than on a lower portion of said electrode layer; and (iv) covering said pairs of electrodes with at least one protective layer.